Synthesis of phthalocyanines from omega-chlorine or omega-bromine substituted omicron-tolunitriles



Patented Feb. 1,1949

SYNTHESIS OF PHTHALOCYANINES FROM w-BROMINE SUBSTI- TUTED o-TOLUNITRILES 1 Robert E. Brouillard, Bound Brook, N. J., and Erwin Baumgarten, Westerleigh, Staten Island, N. Y., assignors to American Cyanamid Company, New York, N. Y., a corporation of Maine w-CHLORINE OR No Drawing Application June 2, 1947, Serial No. 751,989

importance because of their valuable color characteristics. In the past these pigments have been prepared on a large scale from phthalic anhydride or phthalonitrile. These processes have introduced considerable practical difficulties which have been reflected in increased costs.

When the phthalonitrile process is used, expensive and complicated equipment is required for the high temperature catalytic conversion of phthalic anhydride into phthalonitrile; this step is also subject to a considerable explosion hazard because of the danger of cracking ammonia at the high temperatures used. When phthalic anhydride is used directly without first forming the nitrile, a hard fused reaction mass is obtained which is particularly difficult to stir and heat evenly and involves crushing and grinding operations after the pigment has been formed.

Bothof the processes starting from phthalic Claims. (Cl. 260314.5)

anhydride or phthalonitrile are also subject to tion is not entirely. clear and it is not intended to limit the present invention to any particular reaction theory.

The omega chloro or bromo o-tolunitriles used in the present invention may have froml to 3 halogen atoms in the methyl group. They include such compounds as w-chloro-o tolunitrile,

w, w-dichloro-o-tolunitrile, w, w, w-trichloro-o-tolunitrile, and the various -bromo-o-tolunitriles such as w,w-dibromo-o-tolunitrile. The omega chloro or bromo o-tolunitriles may also carry nuclear substituents. Typical of such substituents are fluorine, chlorine, bromine, nitro, carboxy, sulfo and trifluoromethyl.

It is an advantage of the present invention that the omega halogeno-o-tolunitriles may be prepared by conventional methods which are usein] in side chain halogenation. For example,

2 halogenatingagents such as chlorine, bromine, sulfuryl chloride, phosphorus pentachloride, and the like, may be employed. In addition, conditions aiding side chain halogenations such as irradiation with ultra-violet light may be employed as well as catalysts when necessary. The degre of replacement of hydrogenatoms in the methyl groups with chlorine or bromine atoms is readily controllable by the customary variations in reaction conditions, it being an added advantage that close or critical control is entirely unnecessary because the exact number of chlorine or bromine atoms introduced is immaterial.

The omega chloro or bromo o-tolunitriles react with th same type of nitrogen compounds as does phthalic anhydride to form phthalocyanine pigments. That is to say, they react with compounds such as ammonia and those which are capable of generating ammonia under the reaction conditions. Such compounds,for example, are urea, guanylurea, biuret and the like. These compounds need to possess no particular high degree of purity. In fact, mixtures of these compounds give as good or in some cases better yields than do the, pure reagents. This is an additional advantage of the process of the present invention.

The ratios of omega chloro or bromo o-tolunitrile to the nitrogen containing reactants may vary widely although, of course, the nitrogen containing compound must be present at least in stoichiometric amounts. In general, a small excess has been found desirable. The amount of excess will vary somewhat from one reagent to another and also with the conditions of the single portion either before or after the omega chloro or bromo o-tolunitrile has been added to the reaction mixture. It is equally feasible to add the nitrogen containing compound in small portions either in the initial stages of the reaction or during the entire period.

The metal phthalocyanines which may be produced by th process of the present invention include copper phthalocyanine, cobalt phthalocyanines and nickel phthalocyanines. to say, phthalocyanines of the metals having atomic numbers 27 to 29. A metallifercus reagent containing the desired metal must, of course, be used. Examples of such metalliferous reagents are copper powder, cupric chloride, cuprous chloride, cupric bromide, cupric sulfate, cobalt That is Zmally be advantageous where volatile reagents are employedz a {ThG pigmentsv obtainedby the: process "of the 1 alcohol and water. "reaction mixturealone when sufiicient solvent has been employed or the reactionfmixture may chloride; nickel chloride and the like. The

The reaction medium may be varied. Goodresults are obtained when the; reactants are fused without the use of any solvents. In manycases; a however, an organic solvent isdesirable. Excel- J lent results are obtained as far as the-reaction is concerned and the solvent also increases the I to producesolvent stable pigments.

but large excesses are unnecessarily wasteful and while they do not interfere with the reaction, any large excess of metalliferousagent will create an additional separation problem.

fluidity of the reaction mixture. various types of organic solvents may beused. We prefer to use organic solvents having a slight oxidizing action, such as, for example, aromatic nitro compounds. Nitrobenzene because ofits ready. avail;- ability is one of the bestsohrentstoi' use, :and: it

a exerts a particularly, beneficial effect: It"'-'is-. by

no means necessary to add enough solvent to-dis solve-all of the reactants. Onthe" contrary, the

amount of solventwhich' renders the reaction mixture fluid and 'stirrableisfquit adequate. It is another advantage of the present invention that temperature control is not critical The reaction will proceed withina range of 150-250 C. .-;Optimum;temperature will varywith th'e' reagents, the solvent usedand the time an'dspee'd of reaction desired. aUsually optimumresultswill ,bepbtained within a preferred'temperature range of l80200 C. v ;'Ifhe process may be carried out'uniier ordinary pressure orin an autoclaveg; The latter will norgaseous or :very

present. invention are readily purified anddorn'ot introduce any'problem which isniore difficult,

than that encountered inthe ordinary. processes which have been used hithertoflThe present in;- vention, therefore, is not concerned :'.primarily with anyparticular method of isolating or purifying the pigments. The standard" procedures I may be. employed... We have ifOUJfld that a very efiicient methodis to use filtration-followed by washing ofi the'filter cakewith 'solventssuch as The filtration may be ofv the be drowned in water and the resulting slurrymay then be filtered.

;In addition to the advantages presented-bythe "process of the present invention in the production of known phthalocyanine pigments, it is pos sible now to produce substituted pigments which were hitherto either unknown or not economically produceable.

. Ihe present process, when usedwith a solvent avoids difiiculties attendant on the'old methods inwhich the reaction has become a hard solid .mass. In this preferred modification of the pres- However, the pigments may be purified or COIIdi-y tionedinthe usual ways. For example, by acid a n an wet or dry indi d, b en n The pigments are also succeptible to treatment I able means. e

.trob'enzeneand 151parts of urea'is refluxed until The invention will be illustrated in greater detail in 'conjunlction with theifollowing specific ex- "amples. The parts are by weight.

Ercample 1 67 partsof nitrobenzene, and 1 part of anhyutes to 120 C. while ammonia. is being passed 7 through the reaction mixture. The mixture is then. refluxed until pigment formation is complete. The resulting mixture is filtered hot and the filter cake washed successively with nitrobenzene, acetone, dilute hydrochloric acid, dilute sodium hydroxide, and water. The copper I .phthalocyanine thus obtained is dried to give a bright bluepigment of good quality which may bepurified further by acid pasting or other suittame:

LAzmixture of 5 parts'of o -chloro o-tolunitrile, 1 part-of anhydrous cHpficchloride, 56 parts nipigment formation is" substantially complete. The reaction mixturegis filtered. hot and thefilter cake washed successivelywith nitrobenzene, acetone, dilute hydrochloric acid, dilute sodium hydroxide, and water. The copper-phthalocyanine thus obtained'isrdried to give *a bright blue which may be purifiedfurther if desired.

' f ,Erbttmii'les A'mixture of lo-parts of'oasdichloro o-tolunitrile, 3E5 parts of anhydrous"cupricchloride, and '56part's of 'nitrobehzene is refluxed while a current of ammonia'is passed through 'untilfpigment formation is substantially. complete. The bright blue pigment so obtained is isolated and purified in thefsame manneras isthe" product obtained by theprocedure described: in :Example 1.

' a a ifEic'dihple '4 r A mixture oifffi-parts of o.v-,w-dichloro-o-tolunitrile, 2 parts'o'flanhydrous cupric chloride, and 56 parts "of nitrobenzenefis' heatediin an atmosphere o'f'arnni'onia to ab'out200 C. at l50-psi. 'pressurein an autoclavefintil pigment formation iscoinplete. ffl'he bright blue copper phthalocyaiiihe pigmeht'so obtained is isolated and purified in'the 'same-manne'r" as is the product obtained by" thep'roc'e'dui'edescribed in Examplel. 5 T

f Example 5 mixture of 5 partsofw,o='dichloro-o-tolunitrile,-'2 parts of cupric' chloride, -56 .parts' nitrobenzene, and. 15 parts of urea is :refluxeduntil pigment formation is substantially "complete. The 'blue copper 'phthalocyani'ne pigment so formed is isolated and purified in the's'ame manner as .isthe product in Example I rmmbze-s obtained by the procedure Amixture of 5 parts of w,w-dibromo-o-tolunitrile -1 .part anhydrous 'cupric chloride, 5'7 parts of 'nitrobenzene and 5 parts of'urea is refiuxed until pigment formation is complete. The reaction mixtureis worked up and the bright blue pigment so obtained'purifiedfln the same manner as is the product-obtained by the proedure d s rib dfin' x mp z:

Example 7 Example 8 A mixture of 10 parts w,w,w-l311ChlOrO-O-tO1unitrile, 3 parts of anhydrous copper sulfate, 10 parts of urea, and 56 parts of nitrobenzene is heated at reflux temperature until pigment formaticn is substantially complete. The reaction mixture is worked up and the bright blue pigment so obtained purified in the same manner as is the product obtained by the procedure described in Example 1.

What we claim is:

1. A process for preparing phthalocyanine pigments which comprises reacting an omega halogeno 0-to1unitrile, the halogen having an atomic weight of at least 35 and not more than 80, at a temperature of 150-250 C. with a compound selected from the group consisting of ammonia and compounds capable of generating ammonia at the reaction temperature and mixtures thereof, and a metalliferous reagent, the metal of which has an atomic number of 27 to 29.

2. A process for preparing phthalocyanine pigments which comprises reacting an omega chloro o-tolunitrile at a temperature from 150-250 C. with a compound selected from the group consisting of ammonia and compounds capable of generating ammonia at the reaction temperature and mixtures thereof, and a metalliferous reagent, the metal of which has an atomic number of 27 to 29.

3. A process for preparing copper phthalocyanine pigments which comprises reacting an omega halogeno o-tolunitrile, the halogen having an atomic weight of at least 35 and not more than 80, at a temperature from -250 C. with.

a compound selected from the group consisting of ammonia and compounds capable of generating ammonia at the reaction temperature and mixtures thereof in an organic solvent in the presence of a cupriferous reagent.

4. A process for preparing copper phthalocyanine pigments which comprises reacting an omega chloro o-tolunitrile at a temperature from 150-250" C. with a compound selected from the group consisting of ammonia and compounds capable of generating ammonia at the reaction temperature and mixtures thereof in an organic solvent in the presence of a cupriferous reagent.

5. A process according to claim 1 in which the reaction is carried out in an organic solvent.

6. A process according to claim 2 in which the reaction is carried out in an organic solvent.

7. A process according to claim 3 in which the reaction is carried out in a nitrobenzene reaction medium.

8. A process according to claim 4 in which the reaction is carried out in a nitrobenzene reaction medium.

9. A process for producing copper phthalocyanine which comprises reacting omega-chloroo-tolunitrile with urea in nitrobenzene at 150- 220 C. in the presence of cupric chloride.

10. A process for producing copper phthalocyanine which comprises reacting w,w,w-trichloroo-tolunitrile with urea in nitrobenzene at 150- 220 C. in the presence of cupriferous reagent.

ROBERT E. BROUILLARD. ERWIN BAUMGARTEN.

No references cited. 

